THE CITY surpassed its highest September rain record 18 days into the month this monsoon as the Santacruz observatory recorded 921.3 mm rain from September 1 till 8.30 am on Wednesday. The all-time record for rainfall in September until now was 920 mm, recorded in 1954. The average rainfall for the month is 327.1 mm.
The India Meteorological Department (IMD) has issued a red alert for Mumbai on Thursday with forecast of "extremely heavy" rain at isolated places. The Met department has also issued an orange alert for Friday with forecast of "heavy to very heavy rain" at isolated places. For Thane, an orange alert is issued for Thursday as well as Friday. Following the red colour warning, according to the IMD, localised flooding and traffic disruptions could be the expected impact. The adjoining area of Palghar is likely to receive "heavy rain" at isolated places on Thursday, said the IMD. It has issued an orange alert (authorities to be prepared) for Raigad with forecast of "heavy to very heavy" rain at isolated places.
"A low pressure is likely to develop over west central Bay of Bengal and adjoining areas of coastal Andhra Pradesh during the next 24 hours. In such a situation, fairly widespread to widespread rainfall with isolated very heavy to heavy rainfall is likely over Maharashtra on September 18 and 19," read the forecast and warning issued by the IMD.
It further added, "Probable extremely heavy falls over ghat areas of Madhya Maharashtra and North Konkan (including Mumbai) over the next 48 hours."
Development of low-pressure areas has been keeping the monsoon active and has led to a delay in its withdrawal. The southwest monsoon spans across four months in Mumbai from June to the end of September. This still leaves nearly 12 more days of rain. Last monsoon, the September average rainfall was just 73.1 mm while the lowest September average rainfall was 34.7 mm recorded in 1987.
From June 1 to September 18, Mumbai received 3,475.2 mm rainfall. It is the second highest seasonal rainfall recorded since 1954. The IMD has been recording rainfall for Mumbai since 1954.
The highest seasonal rainfall was recorded in 1958 at 3,759.7 mm while the lowest seasonal rainfall was recorded in 1986 at 1,341.9 mm. In 24 hours, ending at 8.30 am on Wednesday, the IMD’s Santacruz observatory recorded 7.6 mm rain while the Colaba observatory recorded 28.8 mm rain in the same time frame. Neighbouring areas like Panvel recorded 114.6 mm rain, Vasai received 21 mm, Dahanu 38.3 mm, Virar 22 mm, Palghar 34 mm in 24 hours ending at 8:30 am on Wednesday.